Real fleets mix regimes: a driver does local work under GB domestic rules on Monday, then a longer run in scope of the assimilated EU rules on Tuesday, sometimes both on the same day. The law has an answer for how the limits combine, and it always leans toward the stricter rule. DVSA’s guidance on mixed driving is short but absolute, and every operator running mixed work should have it pinned to the wall.
When a driver works partly under assimilated or AETR rules and partly under GB domestic rules in a day or a week, three principles govern everything, and the assimilated rules take precedence:
Notice the asymmetry: each regime consumes the other’s allowances, and neither lets the other’s work masquerade as rest. You cannot do a morning of domestic driving and call it your break before an afternoon in scope of the assimilated rules.
The GB domestic limit, a maximum of 10 hours driving in a day, must always be obeyed, whatever mix of work the day contains. But at any time the driver is actually driving in scope of the assimilated or AETR rules, all the assimilated and AETR driving limits apply as well: the 4.5-hour driving block, the daily and extended daily limits, and the weekly and fortnightly ceilings. The two limits run in parallel and the driver must stay inside both.
The GB domestic duty limit, no more than 11 hours on duty in any 24-hour period, always applies. But on any day that includes assimilated or AETR driving, the assimilated duty framework takes over: a maximum duty day of 13 or 15 hours, depending on the daily rest required, and assimilated or AETR breaks must be taken within those duty periods. So a mixed day is capped by whichever constraint bites first, and the 45-minute break regime applies to the in-scope driving.
This is where mixed work gets genuinely tricky. All drivers who drive in scope of the assimilated or AETR rules must comply with the sector-specific working time rules, which carry the same rest requirements as the assimilated drivers’ hours rules. In practice that means a driver who does GB domestic work on some days or weeks must still follow the assimilated rest requirements, unless they are classed as an occasional mobile worker.
For occasional mobile workers the guidance is more forgiving but still precise:
The practical mistake is letting a driver stack five GB domestic days then roll straight into an in-scope run. That can breach the six-times-24 rule before the week’s driving even begins.
Mixed work means mixed records. Assimilated or AETR record keeping always applies in addition to GB domestic record keeping, even for occasional mobile workers. On any day with a journey under both regimes, the driver keeps records under both sets of rules.
Under the assimilated rules, all non-assimilated and non-AETR work, including secondary employment, must be recorded as “other work”, using an analogue chart, a digital or smart tachograph printout, or the manual input facility. Records must also be kept for rest days and for annual or sick leave. And if asked, a driver must be able to produce assimilated/AETR records, including the driver card if held, for the current day and the previous 28 calendar days, plus any GB domestic records.
Mixed driving is lawful and common, but it is governed by the strictest reading of both regimes at once. Treat it that way and it stays simple.